Buildings

Shapes

Buildings are collections of basic blocks. With blocks comprised of smaller blocks that are either terminal or non-terminal.
Components: footprint, vertical profile, roof.
A building’s footprint is a collection of same size rectangles. This is done in a pattern of grid cells that are either filled (1) or empty (0).
Outer walls represent facades.
Types of roofs: gable, hip, cross-gable.
Allow collection of closed shapes to contribute to building shapes with intersections to be handled, e.g. boxes + cylinders.
Occlusions: one object in front of another.

Interior is ignored, windows are opaque and textures are used a replacement for geometry.
Components: overall geometry and facade elements, e.g. windows, doors, etc.
To simplify, facades are rectangles with doors and windows flat against the wall.
Approach: divide facade into 2D grid of cells, each cell has various attributes (e.g. style, size, position), convert each cell into a set of textured quads. Rows of cells are separate floors with columns representing aligned windows.
Evaluate rules based on cell attributes, mark one ground floor cell as a door, then randomly pick window types using the same style in rows or columns.